R600/SI: Fix moveToVALU when the first operand is VSrc.

Moving into a VSrc doesn't always work, since it could be
replaced with an SGPR later.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195042 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed